Method of casting composite roll



May 20, 1958 KoKlcHl oTANl METHOD oF CASTING COMPOSITE Rom.

Filed Jan. 8, 1954 #gama Kalf/CH 071W/ United States Patent() p 2,835,008 METHOD OF CASTING COMPOSITE ROLL Kokiclli Otani, Minato-ku, Tokyo, Japan Application January 8, 1954, Serial No. 402,894

[Claims priority, application Japan October 14, 1953 2 Claims. (Cl. 22201) This invention relates to a method of casting composite roll and, more particularly, to a method of casting roll characterised in that molten cast steel or cast iron is poured down from the top of a mould into a steel pipe surrounded or not surrounded by steel rods installed at the center of the said mould consisting of the upper neck sand mould, body portion metal mould, and lower neck sand mould which is provided with a gate and a canal and, at the same time or before or after that, molten chilled cast iron or cast steel containing other components s introduced into the cavity of the said mould around the said central steel pipe through the said canal and gate, and lastly molten cast iron or cast steel is poured down from the top as feeding material.

The method of casting composite roll according to the present invention will be explained referringbto an embodiment of the invention shown in the accompanying draw ings. In the drawings, Fig. 1 is a vertical cross section showing an apparatus with which the method of this invention is carried out, Fig. 2 a transversal cross section thereof, taken along line 2--2 of Fig. l, Fig. 3 a transversal cross section of the same in case steel rods are used surrounding the steel pipe, and Figs. 4 and 5 transversal cross sections of products obtained by this method. Referring to .the drawings, sand neck moulds 2 and 3:,l the latter being provided with a' gate 5 and a canal 4, are arranged connectively at the top and bottom of a metal mould 1 and a steel pipe b is installed at the center of the cavity a of the mould 1, the upper part of the said pipe being held by wires 6.

Molten cast steel c is poured into the said steel pipe b from the top opening e resulting in that the said steel pipe b fusing partly turns crimson. Simultaneously at that time, molten chilled cast iron is led into the lower neck sand mould 3 through'the canal 4 and the gate 5 and final ly fills up the cavity of the mould around the central steel pipe b. Subsequently, molten cast iron e is poured as feeding material from the top of the upper sand mould.

In this case, as the temperature of the molten cast steel cis about l500 C., the steel pipe b is caused to become half-fused and, as the outside of the steel pipe b becomes covered by molten chilled cast iron d (about l300 C.) the outer surface of pipe b fuses with the cast iron, while the steel pipe b located between the east steel and the cast iron will prevent diiusion of the molten cast steel into the molten cast iron d. Nevertheless, due to the fusion of the pipe, the pipe, the cast iron and the cast steel will combine together without forming a boundary there between, and the three elements will solidify into one unit ln addition, as the inner cast steel c is annealed by the surrounding molten chilled cast iron d, the structure thereof becomes mild and durable. Onthe other hand, the exterior 7 of the chilled cast iron d is sharply cooled by coming in contact with the metal mould 1 and is chilled to form a hard structure, the inside thereof remaining'a durable and strongstructure. The thickness of the steel pipe b differs according to the size of a product to be pre` 2,835,003 Patented May 20, 1358 ICC Components of chilled cast iron 5 gi 5 0' 05 Components of east steel S30 gil Agri (f5 (05 For carrying out the method of the present invention, I used a mould the dimension of which was as follows:

J Inches Calibre of the metal'mould 30 Length of the same 44 Outside diameter of the steel pipe 8 Thickness of the same 0.25

ln this case, it is possible to cause the structure of the molten chilled cast iron to solidify stronger by coating aluminium powder etc. on the outer surface of the steel pipe which has been cleaned and to let the cooling speed of the molten cast iron d and steel pipe b to decrease owing to the radiation of combustion heat which is caused by the air which exists in the molten chilled cast iron.

ln case of making a product of big dimension with a thin steel pipe, it is possible to prevent the inner cast steel to diffuse into the cast iron by placing steel rods f cornpactly around the said steel pipe b.

What I claim is:

l. A method of casting rolls having an inner portion of tough metal and an outer portion of hard metal in a vertical mold comprising the steps of placing a separator in the form, of a steel pipe going through the whole length of the mold and having its lower end closed by the mold into the same; completely surrounding said steel pipe with a plurality of steel rods having a length equal to the length of said pipe and axes parallel to the steel pipe axis; and casting the inner portion in the steel pipe from the top of the steel pipe downwardly and simultaneously casting the outer portion in the mold surrounding the steel pipe from the mold bottom upwardly.

2. A method of casting rolls having an inner portion of tough metal and an outer portion of hard metal in a vertical mold comprising the steps of placing a separator in the form of a steel pipe going through the whole length of the mold and having its lower end closed by the mold into the same; completely surrounding said steel pipe with a plurality of steel rods having a length equal to the lengths of said pipe and axes parallel to the steel pipe axis; and casting steel of high temperature into the steel pipe from the top of the steel pipe downwardly to form said inner portion and simultaneously casting cast iron forming said outer portion fuses with said steel rods and Y with the outside of said steel pipe to form a single unit; and linally pouring cast iron as feeding material on the top of the mold.

(References on following page) .2 References Cited in the le of this patent UNITED STATES PATENTS Cochran May 8, 1900 Monnot Aug. 3,- 1909 5 Henry Dec. 12, 1911 f McKenna Dec. 1, 1914 Nichols Apr. 6, 1920 Trembour et al. Dec. 1, 1931 FOREIGN PATENTS Germany Dec. 10, 1892 

